The PTT user community is fragmented across several PTT systems, which are based on different technologies and are often incompatible with each other. PTT systems differ from standard direct or party calling system in that they require active management of user control during calls and centralized management of caller groups. Various PTT systems may use different communications and network management standards, as Open Mobile Alliance (OMA) push to talk over cellular (PoC), integrated digital enhanced radio (iDEN), Project 25 Console Subsystem Interface/Inter RF Subsystem Interface (P.25 CSSI/ISSI), terrestrial trunked radio (TETRA), digital mobile radio (DMR), or the like. These different PPT systems use different standards for managing call connections, for managing group membership, and for managing which caller has floor control, or which user is talking.